There is apparently a flesh-eating bacteria living in the River Murray.
The evidence is all over Bill Andrews' leg.
The infection the Murray Bridge resident contracted eight weeks ago could have cost him his life.
He had just got back from a family fishing trip and needed to rinse the outboard motor on his boat, so he took it down to the riverfront at Hume Reserve.
"We wouldn't have been in any deeper than my knees," he said.
"A couple of days after that, on the Sunday morning, it felt like someone was under the blanket, cutting my leg off with an electric saw – excruciating pain."
He collapsed on the floor in his lounge room, his wife called an ambulance and he was rushed to hospital.
After several days in the Murray Bridge hospital, with doctors and nurses crowding into his room to see the strange affliction, Doctor Jacqui Wagner sent him on to the Royal Adelaide.
He wound up staying there for three weeks.
He lost 20 per cent of the flesh on his calf during three attempts to cut out the infection, which was identified as something called shewanella algae.
SA Health did not answer questions from The Standard about how many shewanella infections had been recorded in South Australia, or where and when they had emerged.
But the department’s principal advisor on water quality, Dr David Cunliffe, said cases were "very uncommon".
"Shewanella bacteria are usually found in marine environments, generally in warm seawater, although forms of the bacteria can also exist in other water bodies and soil," he said.
"Shewanella can cause serious skin or soft tissue infections and ear infections.
"People with low immune systems, abrasions or open wounds are most at risk from exposure to bacteria that are found in the natural environment such as shewanella.
"Any wounds and abrasions should be kept covered during recreational exposures."
If not treated, infections can lead to amputation or death, according to health authorities in the US.
However, shewanella is not a notifiable condition, so no public warning needs to be issued when someone contracts it.
Mr Andrews thinks that should change.
His daughter, Kylie Komar, phoned the Environment Protection Authority and SA Health to demand an explanation, but was told it was up to the doctors treating him to call for a public warning.
She worried that the severity of his condition deserved a bigger response.
"It got pretty ugly fairly quick," she said.
"In hindsight, going back, we probably could have read a little bit in between the lines that it was probably worse than we were thinking.
"It's an amazing credit to Dr Jacqui Wagner for identifying it before it went any further ... (and) Murray Bridge hospital and the RAH were amazing."
Dr Wagner declined an offer to tell her side of the story. Health Minister Jack Snelling did not respond to a request for comment.
- Editorial: Tell us more about shewanella, minister